Scientific Abstract Presentations: Reconstructive Session 8 Saturday, September 28 Sat, Sep 28 5:00-6:00 p.m. PDT

Introduction: Patients with complex ventral hernias often encounter challenges due to medical comorbidities, notably obesity1. Despite notable advancements in abdominal wall reconstruction techniques, access to these procedures remains limited for a substantial portion of patients due to BMI. This exclusionary barrier underscores the pressing need to explore alternative surgical strategies that accommodate patients with higher BMIs.2,3 This study explores the outcomes of complex ventral hernia repair utilizing epigastric artery perforator sparing skin incisions, component separation, and wide-spanning retro rectus mesh reinforcement in patients with a BMI greater than or equal to 40 kg/m2.

Methods: We conducted a retrospective review of patients who underwent open ventral hernia repair with component separation and mesh reinforcement by a single surgeon between 2010 and 2022. Data analysis focused on class III obese patients with BMI ≥ 40kg/m2. Utilizing the median BMI of the cohort (BMI 45.3kg/m2), patients were subcategorized into two groups: Group one with BMI 40-45.3 and group two with BMI>45. The outcomes evaluated were postoperative infection, return to operating room (ROR), hospital length of stay (LOS), and hernia recurrence.

Results: A total of 209 patients, with a BMI greater than 40kg/m2, met the inclusion criteria for our study. The majority were female (73% vs 27%, p<0.01). Forty-eight patients experienced postoperative wound infections, with a higher rate in Group two compared to Group one (28.1% vs 18.4%, p<0.05). Overall, 41.2% of patients returned to the operating room for a secondary procedure at some point during the follow up. The most common procedure performed was debridement and closure (77% of all ROR). Fewer patients in Group one returned to the operating room compared to Group two (25.8% vs 51.9%, p<0.001). We did not observe a statistically significant difference in the LOS between the two groups. The overall recurrence rate of hernia was 4.4%, which did not differ between the groups. Conclusion: Complex ventral hernia repair with epigastric artery perforator sparing skin incisions presents as a viable option for class III obese patients.4 While our findings suggest that recurrence rates may align with those of the general population, it's crucial to note that wound complications may be elevated, particularly in individuals with higher BMI. Therefore, while this procedure remains feasible, optimizing presurgical factors, including BMI reduction, is essential to mitigate postoperative challenges and ensure favorable outcomes in this patient cohort.

References: 1. Fischer JP, Wink JD, Nelson JA, et al. Among 1,706 cases of abdominal wall reconstruction, what factors influence the occurrence of major operative complications? Surgery. 2014;155:311–319. 2. Giordano SA, Garvey PB, Baumann DP, et al. The impact of body mass index on abdominal wall reconstruction outcomes: a comparative study. Plast Reconstr Surg. 2017;139:1234–1244. 3. Desai KA, Razavi SA, Hart AM, et al. The effect of Bmi on outcomes following complex abdominal wall reconstructions. Ann Plast Surg. 2016;76(suppl 4): S295–S297 4. Oleck NC, Liu FC, Conway M, et al. Complex Ventral Hernia Repair in the Class III Morbidly Obese Patient. Ann Plast Surg. 2019;82(4):428-434. doi:10.1097/SAP.0000000000001656

Introduction: Since the COVID-19 pandemic, numerous studies have demonstrated the virus' activation of a pro-inflammatory cascade that in turn generates a substantial increase in hypercoagulability. The correlation between COVID-19 infection and perioperative complications, particularly venous thromboembolism (VTE), has been underscored across several surgical specialties. While individuals undergoing plastic surgery procedures generally demonstrate a less than 2% incidence of VTE outcomes, the post-COVID era data remains elusive. This study sought to elucidate the relationship between COVID-19 infection and the risk of VTE outcomes across plastic surgery procedures.

Methods: Plastic surgery procedures were identified in the 2012-2022 National Surgical Quality Improvement Program databases by CPT code, with the pre-pandemic period being defined as 2012 to the first quarter of 2020 while the pandemic period was designated as the second quarter of 2020 to 2022. Demographic and clinical characteristics were collected for each case. The outcomes of interest were the postoperative occurrence of VTE, defined as deep vein thrombosis (DVT) or pulmonary embolism (PE), and the occurrence of any postoperative complication. Propensity score matching based on potentially confounding covariates was used twice to 1) compare overall rates of VTE between the pre-pandemic era and the pandemic era, and 2) quantify the predictive impact of COVID-19 diagnosis in years 2021-2022 on risk of VTE and overall postoperative complications with logistic regression (p<0.05).

Results: 269,006 plastic surgery cases were identified, comprising largely general breast (77.3%) and trunk (11.3%) procedures. Non-breast free tissue transfer cases were associated with the highest rates of DVT (1.3%) and trunk procedures with the highest rates of PE (0.71%). Patients who experienced VTE were more likely to be older, of a higher BMI, and male, and also shared a higher comorbidity burden in factors like diabetes, immunosuppression, hypertension, and existing cancer diagnosis (p<0.001). After propensity score matching, the overall rate of VTE after the onset of the COVID-19 pandemic (0.52%) was not significantly different from the rate in the pre-pandemic era (0.48%) (p=0.22). Within pandemic years that contained data on COVID-19 diagnosis (2021 and 2022), patients who had COVID-19 diagnosis were associated with a significantly higher rate of VTE (1.6%) than those who did not have a COVID-19 diagnosis (0.5%) (p=0.0054). In the matched cohort, the impact of COVID-19 diagnosis did not significantly predict risk of VTE (p=0.56), but it did significantly predict risk of overall postoperative complications (p=0.0032).

Conclusions: The COVID-19 pandemic introduced a novel array of complications within surgical specialties, chief among those being increased risk of hypercoagulability. While COVID-19 diagnosis itself did not predict risk of VTE upon matched analysis, it was a significant predictor of overall postoperative complications. Our findings underscore the importance of considering patient characteristics and the evolving landscape of infectious diseases in the assessment and management of thromboembolic and general postoperative complications in plastic surgery patients with the potential need for restructuring of perioperative thromboprophylaxis.

Introduction

Autologous tissue transfer is the preferred method for breast reconstruction by plastic surgeons, evolving with technology and microsurgical skills, expanding its donor site options. Flap choice depends on breast volume needs and donor site availability, with the abdomen being predominant. Muscle-sparing DIEP flap is preferred for its safety. Post-harvest, tissue undergoes ischemia-induced changes, such as a shift from aerobic to anaerobic metabolism, impaired vasodilation, and accumulation of oxygen free radicals, increasing complications like flap failure or fat necrosis. Intraoperative ischemia over 60 minutes heightens postoperative risks. This review aims to identify and address these ischemia-induced complications to enhance breast reconstruction outcomes.

Methods

A systematic review and meta-analysis were conducted following PRISMA guidelines. PubMed, Embase, and Web of Science were searched. Studies were included if they reported on free flap breast reconstruction and provided data on ischemia time and complications. Studies were divided into cohorts based on mean ischemia time (<60 vs. >60 minutes). Demographics, mean ischemia time, BMI, and complication rates were analyzed. The MINORS tool assessed study quality.

Results

Out of 3745 articles resulting from the initial search, 18 studies were included for qualitative and quantitative analysis, encompassing 5548 patients. In the cohort with ischemia time <60 minutes, the mean age was 50.8 years [95% CI: 50.23; 51.40], with a mean BMI of 26.04 [95% CI: 22.93; 29.15] and mean ischemia time of 44.92 minutes [95% CI: 35.33; 54.51]. Total complications occurred at a rate of 15.95 [95% CI: 9.87; 24.73], total flap loss at a rate of 2.05 [95% CI: 1.73; 2.43], partial flap loss at a rate of 1.44 [95% CI: 0.84; 2.45], venous congestion at a rate of 0.48 [95% CI: 0.33; 0.68], hematoma at a rate of 1.09 [95% CI: 0.22; 5.21], fat necrosis at a rate of 1.17 [95% CI: 0.93; 1.47], and infection at a rate of 0.45 [95% CI: 0.05; 3.45]. In the cohort with ischemia time >60 minutes, the mean age was 47.9 years [95% CI: 45.84; 50.06], with a mean BMI of 26.32 [95% CI: 24.20; 28.44] and mean ischemia time of 93.77 minutes [95% CI: 72.38; 115.16]. Total complications occurred at a rate of 17.72 [95% CI: 10.57; 28.18], total flap loss at a rate of 1.90 [95% CI: 1.26; 2.84], partial flap loss at a rate of 2.23 [95% CI: 1.53; 3.23], venous congestion at a rate of 1.73 [95% CI: 1.13; 2.65], hematoma at a rate of 2.89 [95% CI: 2.08; 4.00], fat necrosis at a rate of 4.63 [95% CI: 3.58; 5.97], and infection at a rate of 2.64 [95% CI: 1.87; 3.72].

Results

This study demonstrates that ischemia time significantly impacts postoperative complications in free flap breast reconstruction. Patients with ischemia times exceeding 60 minutes showed elevated rates of complications, including total flap loss, partial flap loss, venous congestion, hematoma, fat necrosis, and infection. These results emphasize the importance of considering ischemia time when predicting surgical outcomes.

Background Hidradenitis suppurativa (HS) is a debilitating chronic inflammatory disease affecting the intertriginous areas (1). The existing surgical outcomes data is heterogeneous which can limit its clinical applicability (1,2). This investigation sought to identify factors associated with postoperative complications and HS recurrence in an axillary hidradenitis population.

Methods This retrospective study included patients who had surgical treatment for axillary hidradenitis at our institution between 2013 and 2021. Demographics, postoperative outcomes, and axillary recurrence were evaluated using univariate analysis and multivariate regression models.

Results A total of 57 patients (mean age 33.19 ± 10.3, mean BMI 35.34 ± 6.97) had surgical treatment of their axillary HS. Most (80.7%) patients identified as black and were female (91.2%). The median follow-up time was 22.1 months (IQR: 12.13, 31.95). A total of 52 patients underwent direct excision (80.7% unilateral) and 5 had unroofing procedures. Thirty-four patients' wounds were closed primarily, 15 patients healed by secondary intent, 5 patients received skin grafts, 2 patients were partially closed with sutures and packing, and 1 patient underwent pedicled flaps. Twenty-seven patients experienced complications. Two patients experienced partial skin graft loss, 3 patients developed seromas, 13 patients had a wound dehiscence greater than 1 cm, and 5 patients had surgical site infections. Hurley score, active immunosuppression, diabetes, and smoking status were not associated with post-operative complications. BMI was the only factor associated with an increased risk of postoperative complication in both univariate and multivariate analysis (OR 1.103, 95% CI 1.010 – 1.218, p = 0.0372). There was no association between procedure type and post-operative complication (p = 0.3558). Of the 52 patients who had at least 6 months of follow-up, the overall axillary recurrence rate was 19.2%. Hurley score, diabetes, and BMI were not associated with HS recurrence. Unroofing was associated with an increased risk of recurrence (OR 16.07, 95% CI 1.89 – 185.27, p = 0.0134).

Conclusions This study of a more uniform population with a specific site of HS management showed that diabetes, active immunosuppression, and smoking status are not associated with an increased risk of postoperative complications, but elevated BMI was. Interestingly disease severity, measured by Hurley score, was not associated with an increased risk of post-operative complication or disease recurrence.

References 1. Mehdizadeh A, Hazen PG, Bechara FG, et al. Recurrence of hidradenitis suppurativa after surgical management: A systematic review and meta-analysis. J Am Acad Dermatol. Nov 2015;73(5 Suppl 1):S70-7. doi:10.1016/j.jaad.2015.07.044

2. Tang B, Huang Z, Yi Q, Zheng X. Complications of hidradenitis suppurativa after surgical management: A systematic review and meta-analysis. Int Wound J. Apr 2023;20(4):1253-1261. doi:10.1111/iwj.13945

Introduction

Microtia reconstruction relies on meticulous preoperative planning as well as the ability to translate that planning to execution during the operation. Symmetry to the contralateral ear is one of the main goals of unilateral microtia reconstruction. An overwhelming preference, from both physicians and patients, for autologous rib reconstruction to achieve this symmetry prompts the need for a comprehensive way to measure the unaffected ear as well as design and localize the reconstructed ear. While the most popular technique today, the Nagata technique, began with free-hand drawing of the auricular framework, the senior author created a template now used in this technique which provides a systematic method to create the auricle.

Methods

Template development occurs through smoothly connecting several monotonic curves. Making templates whose curves are adjusted to each external ear of each patient would be unrealistically time-consuming and expensive, but it is desirable to prepare several types of template curves so that one approximating the features of the patients' external ears' curves might be available. Image analysis of 50 external ears was completed through gray-scale processing, image thresholding, noise reduction, and polynomial approximation to the 20th degree of the helical curve. This analytical paradigm was applied to approximated curves of the antihelix as well.

Results

There are several templates that can assist physicians in auricle construction including those which help design the ear shape, framework templates, as well as those which assist in localization of the new auricle with respect to other facial anatomic landmarks. The auricular frame templates, developed by the senior author, are based on a curve ratio analysis of a normal auricle and come in 6 different shapes: A1, A2, B1, B2, C1, C2. The letter indicates helical shape: smooth, one flexion point, or two flexion points. The number indicates antihelical shape: square or circular. These 6 auricular frameworks come in 15 sizes ranging from 44mm to 72mm, increasing by increments of 2mm. It is essential to account for skin flap thickness when using these frameworks; for example, when someone wishes to construct an auricle with an ultimate height of 60 mm auricle, the 56 mm height template is used, accounting for the 2 mm skin flap both on top and on bottom.

Using facial landmarks such as the eyebrow and the hairline, surgeons can utilize the ear positioning template to identify the correct location of the auricular rectangle. While these preoperative planning tools are crucial to developing a surgical plan, intraoperative frameworks are available to translate preoperative planning to execution with greater ease during the operation.

Conclusion

Microtia reconstruction using an autologous rib cartilage graft benefits from the use of templates both preoperatively and intraoperatively to achieve bilateral symmetry. Templates offer surgeons both flexibility and guidance in developing a symmetric auricle in microtia reconstruction. These templates are useful in any kind of microtia reconstruction.

Background: The use of mesh in ventral hernia repair (VHR) is held as the gold standard (Luijendijk et al., 2000); however, the risks associated with mesh implantation may have significant consequences for immunocompromised patients (Bueno- Lledó et al., 2017). Transplant recipients require lifelong immunosuppression, putting them at significant risk for severe consequences of postoperative infections (Jackson et al., 2021). Given the risks associated with a potential mesh infection, our clinical practice has shifted away from the implantation of mesh in these patients. This study seeks to evaluate outcomes of VHR in transplant recipients with and without the use of mesh, primarily focusing on postoperative infections and hernia recurrence.

Methods: A retrospective chart review of all ventral hernia repairs performed for transplant recipients performed by the senior author from February 2014 to February 2024 was conducted. Demographics, baseline characteristics, surgical history, intraoperative details, and postoperative outcomes were compared between patients undergoing VHR with and without mesh. Descriptive statistics, chi square analysis, and Wilcoxon ranksum tests were used as appropriate.

Results: A total of 57 patients met inclusion criteria of whom 26 (45.6%) underwent repair with mesh and 31 (54.4%) without mesh. 66.7% had prior liver transplant and 36.8% had prior kidney transplant. Baseline characteristics of both cohorts were comparable. Horizontal hernia size was larger in the mesh cohort (10.4 ± 4.6 vs. 7.7 ± 3.8 cm2, p=0.015). The majority of patients underwent anterior component separation, 22.8% unilateral and 35.1% bilateral. Mesh types chosen were Strattice (53.9%), Ovitex (34.6%), and FlexHD (11.5%). Mesh placement was most commonly retrorectus (32.3%) and intraperitoneal (32.3%). Postoperative length of stay was significantly shorter after repair without mesh (Median: 3 vs. 5 days, p=0.001). Follow-up time was longer after mesh repair (1044 ± 1013 vs. 544 ± 679 days, p=0.032). Overall postoperative complications were comparable (No Mesh 22.6% vs. Mesh 34.6% p=0.314) with a trend towards fewer postoperative infections without mesh (3.2% vs. 15.4%, p=0.106). All patients with mesh infections required reoperation for mesh removal and one patient died from complications of their infection. Recurrence rates were comparable (No Mesh 6.7% vs. Mesh 19.2%, p=0.156).

Conclusion: VHR can be safely performed without mesh in transplant patients, reducing the likelihood of potentially life-threatening postoperative infections without a significant increase in recurrence rates.

References: 1. Luijendijk RW, Hop WC, van den Tol MP, de Lange DC, Braaksma MM, IJzermans JN, Boelhouwer RU, de Vries BC, Salu MK, Wereldsma JC, Bruijninckx CM, Jeekel J. A comparison of suture repair with mesh repair for incisional hernia. N Engl J Med. 2000 Aug 10;343(6):392-8. doi: 10.1056/NEJM200008103430603. PMID: 10933738. 2. Bueno-Lledó J, Torregrosa-Gallud A, Sala-Hernandez A, Carbonell-Tatay F, Pastor PG, Diana SB, Hernández JI. Predictors of mesh infection and explantation after abdominal wall hernia repair. Am J Surg. 2017 Jan;213(1):50-57. doi: 10.1016/j.amjsurg.2016.03.007. Epub 2016 Jun 1. PMID: 27421189. 3. Jackson KR, Motter JD, Bae S, Kernodle A, Long JJ, Werbel W, Avery R, Durand C, Massie AB, Desai N, Garonzik-Wang J, Segev DL. Characterizing the landscape and impact of infections following kidney transplantation. Am J Transplant. 2021 Jan;21(1):198-207. doi: 10.1111/ajt.16106. Epub 2020 Jun 28. PMID: 32506639.

Background

The Area Deprivation Index (ADI) is a composite measure of neighborhood disadvantage that has been shown to significantly impact patient outcomes across several surgical disciplines. ADI takes in to account factors such as income, education, employment, and housing quality. This study sought to examine if ADI can be used to predict complications after breast reconstruction.

Methods

A retrospective review was conducted to identify all patients undergoing either autologous or implant-based breast reconstruction at a single institution. Patient demographics, surgical characteristics, and data on medical and surgical complications were collected. Each patient was assigned an ADI score based on their home address. Multivariate analysis was conducted to identify independent predictors of complications after breast reconstruction.

Results

A total of 506 patients were included in the study, 263 of which were implant-based and 243 of which were autologous-based reconstructions. A total of 5.4% of patients had diabetes, 27.3% were former smokers, 2.0% were current smokers, and 45.5% of patients received radiation. Major complications were identified in 83 patients, minor complications in 112 patients, and no complication in 311 patients. On univariate analysis, increased ADI, type of reconstruction, and operative time correlated significantly with "any complication" (p=0.022, p=<0.001, and p=0.003, respectively); insurance status was not significantly associated with complications. On multivariate regression, increased ADI was identified an independent risk factor for any complications (p=0.007). Increased BMI, diabetes mellitus, and ER positive and HER2 positive tumors were additional independent risk factors for any complications (p=0.01, p=0.02, p=0.0007, and p=0.002, respectively).

Discussion

These data demonstrate that increasing ADI has a significant impact on the development of complications after breast reconstruction. Lack of resources increases a patient's risk of minor complications such as infection or wound complications, but does not impact major complications such as flap loss. Patients and providers should tailor postoperative care and follow-up to help prevent the development of these complications in higher risk patients.

TITLE Free-Flap Phalloplasty Reconstruction for Iatrogenic Micropenis.

INTRODUCTION Many penile enhancement methods have been explored throughout the years. To date, penile enhancement surgery for micropenis that addresses both length and girth with a phalloplasty has not been published in the U.S. We present 3 cases of patients who underwent free-flap phalloplasty to reconstruct micropenis with a notable gain in length and girth.

METHODS This is a single-center case-series of 3 patients who underwent free-flap phalloplasty to reconstruct iatrogenic micropenis. Patient demographics, comorbidities, pathophysiology, procedures performed, complications, and patient satisfaction is discussed.

RESULTS Case 1 56 year-old male with PMH of erectile dysfunction presented with a micropenis of 3.5" outstreched secondary to two penile implant extrusions and infection. A RFFF was designed and tubularized over the denuded phallus once vascular inflow and outflow and nerve anastomosis were established. A urethroplasty was performed on the ventral aspect of the neophallus. The phallus measured 6.5" in length and 5.5" in girth. Complications included hemosiderin deposition that is now resolved. The patient is awaiting penile prosthesis for penetration and has tactile sensation to ¾ of the length from the base. He is satisfied with his reconstruction.

Case 2 69 year-old male with PMH of Peyronie's disease presented to our clinic with a micropenis of 3" outstretched secondary to two penile implant extrusions, partial necrosis, and scarring. A Latissimus Dorsi free flap was used for reconstruction. The phallus measured 11" in length and 8" in girth. There were no major complications. A perineal urostomy was performed at the time of reconstruction. The patient is currently awaiting penile prosthesis placement for penetration. Tactile sensation is present to the tip of the phallus and he is awaiting implant placement. He is satisfied with this reconstruction.

Case 3 64 year-old male with PMH of urethral cancer and a permanent urostomy presented with micropenis secondary to radiation therapy and failed penile implants. A RFFF was used to reconstruct the penis. The final phallus measured 10" in length and 7" in girth. Sensation remains intact and the patient underwent insertion of a penile implant with successful penetration. He remains satisfied with his reconstruction after 3 years.

DISCUSSION In our case-series, free flap phalloplasty for micropenis has shown to be a viable option for patients seeking both length and girth after iatrogenic causes leading to scarring and severe shortening of the penis. The average gain in length was 6" and 3.3" in girth. The latissimus dorsi flap provides a larger skin paddle for length and muscle for girth. No major complications were observed perioperatively. Successful penetration after penile implant was observed in 1 patient, while the remaining two are awaiting penile prosthesis insertion. Patient satisfaction score was high in all patients post-operatively.

CONCLUSION Studies are needed to explore the outcomes of free-flap phalloplasty in iatrogenic micropenis, congenital micropenis, and for males seeking primary aesthetic enhancement of both penile length and girth. The risks and benefits of this procedure should be assessed individually and based on objective findings, functionality, and psychosocial factors.

Objective: Smooth muscle cells are found along pre-collecting and collecting lymphatic vessels, and their function depends on adequate blood supply. The structure of the vasa vasorum of the collecting lymph vessels (VVCL) has been studied, but their physiological role is not well understood. This research aims to examine the relationship between VVCL morphology and blood circulation in limbs with lymphedema, as well as validate ischemic conditions affecting lymphatic vessels.

Methods: The medical records of patients with lower extremity lymphedema who underwent video capillaroscopy during supermicrosurgical lymphaticovenous anastomosis (LVA) surgery were reviewed. The collecting lymph vessels, which were dissected for LVA, were examined using video capillaroscopy (GOKO Bscan-ZD, GOKO Imaging Devices Co., Japan) at 175x and 620x magnification. Software (GOKO-VIP ver. 1.0.0.4, GOKO Imaging Devices Co.) calculated the blood flow velocity of the vasa vasorum of the collecting lymph vessels (VVCL) by measuring red blood cell movement. Based on the video capillaroscopy findings, the VVCL were categorized by morphology, and the morphology types and blood flow velocity of VVCL were compared with the severity grade of lymphosclerosis. Additionally, to investigate the pure effects of hypoxia on lymph endothelial cells, a migration assay of human dermal lymphatic endothelial cells (HDLECs) was performed in hypoxic culture to determine the migration rate of the cells.

Results: The medical records of 20 patients with lower limb lymphedema who had lymphaticovenous anastomosis (LVA) surgery were examined. A total of 67 lymph vessels were evaluated, with varying degrees of lymphosclerosis severity graded as s0 to s3. Video capillaroscopy was used to visualize the vasa vasorum of the collecting lymph vessels (VVCL). The VVCL were categorized into 4 morphology types based on the video images. Blood flow velocity in the VVCL ranged from 0 to 189.3 mm/sec, with an average of 26.40 mm/sec. Statistically significant differences were found in both VVCL morphology and blood flow velocity according to lymphedema severity grade. The diameters of the main VVCL and branches were measured, ranging from 0 to 0.096 mm and 0 to 0.053 mm respectively. Additionally, a migration assay was performed on human lymphatic endothelial cells. The migration rate was 6.344% under normal oxygen conditions and 2.172% under hypoxic conditions after 6 hours, demonstrating hypoxia significantly reduced migration (P=0.00057).

Conclusion: This study found the vasa vasorum of collecting lymph vessels can be categorized into four types, each with distinct features. Changes in the morphology and physiology of the vasa vasorum of collecting lymph vessels (VVCL) are linked to sclerotic changes caused by ischemia affecting these vessels. Additionally, the hypoxic conditions in lymphatic vessels resulting from VVCL damage directly impairs the migratory ability of lymphatic endothelial cells. This may be responsible for worsening of lymphedema.

Introduction: Soft tissue sarcomas (STSs) are mesenchymal tumors that most commonly affect the thigh. With evolutions in chemoradiotherapy protocols, limb salvage with wide resection and reconstruction has become the standard of care. However, patients still face a high rate of surgical complications. Thus, there is a critical need for individualized predictors of outcomes to guide the selection of the best reconstructive approach following oncological resection.

Methods: Data from 151 thigh STS cases were collected, including patient demographics, oncological and surgical variables, and postoperative outcomes. Surgical site occurrences (SSOs) were categorized as minor or major, with major complications indicating reoperation, interventional radiology drainage, or readmission for intravenous antibiotics. Using Bayesian permutation factor importance, variables were ranked based on their impact on the area under the receiver-operating characteristic curve for each outcome. Logistic regression and naïve Bayes machine learning models were developed and validated using a combination of forward selection, backward elimination, and 10-fold cross-validation tests. Model performance metrics included area under the curve (AUC), F1 statistic, classification accuracy (CA), precision, recall, and MCC. The best-performing model was used to construct a nomogram for individualized risk prediction.

Results: Logistic regression models outperformed naïve Bayes in predicting all three classes of complications. On 10-fold cross-validation, the models achieved AUCs of 0.77, 0.73, and 0.72 for SSOs, minor, and major complications, respectively. Nomograms based on this model were developed to facilitate individualized risk prediction and guide reconstructive approaches.

Conclusions: Our machine learning-derived nomograms enable the prediction of three different classes of postoperative complications with different reconstructive techniques, assisting surgeons in selecting the most suitable approach following oncological resection.